The ability of carrot, leek and white cabbage to deplete the soil inorganic
nitrogen (N) pool was studied. All three crops are late-harvested crops wi
th a long growing season, but they have been found to have very different r
oot growth. At their optimal N supply, carrot left 27 kg nitrate-N ha(-1) i
n the top 100 cm of the soil, leek left 87 kg N ha(-1) and white cabbage le
ft only 11 kg N ha(-1), in accordance with previously published differences
in rooting depth among the three crops. Compared at a supply of 160 kg N h
a(-1), 52, 65 and 4 kg nitrate-N ha(-1) was left in the soil by carrot, lee
k and white cabbage respectively. Apart from an extensive root system, whil
e cabbage also had a much higher N-uptake capacity than the two other crops
. The significance of differences in root growth, N-uptake capacity and oth
er factors in determining the ability of the three crops to deplete the soi
l inorganic N pool is discussed.